Sunday, September 14, 2014

Food Contaminants

There is a greater reason than aesthetics to insist on clean hands at all times. Salmonella, the most common form of food poisoning and one that can kill the elderly and infirm, is often transmitted by urine. Diarrhea and dysentery often come from feces.
However, the good news is that the least likely source of food poisoning is a dirty person. The classic case of “Typhoid Mary,” an itinerant dishwasher who spread typhoid wherever she worked, is long gone.

Far more dangerous are bad food storage disciplines. Raw meat and cooked meat must not collide. A butcher or chef who has handled raw meat must not handle any other food item until he’s washed his hands thoroughly in serious soap and water. The quick rinse under the faucet doesn’t do it.

Food stored in a refrigerator must be placed in a way that will not allow accidental drippings from one item to another.

What saves society from regular epidemics of food poisoning is the cooking process. Germs insinuated into food by dirty workers or natural deterioration are destroyed by heat.
Other germs may be present in food from other sources. Chicken has been targeted as the main source of salmonella in the United States. That’s why it should be thoroughly cooked, though it’s not unusual in dubious restaurants to see a little ooze of blood as one cuts into a chicken breast! Such a sight is likely to extinguish the heartiest appetite, so make sure your chicken—and all other appropriate items—are properly cooked, or you’ll lose customers and even risk lawsuits. Apart from the fact that pork tastes better when well cooked (though the French sometimes eat pork chops medium rare!), there is the danger of trichinosis, a common disease carried by pigs that can be fatal to humans. The dietary laws of some religions preclude the consumption of pork, and originally the reason for this may have been practical rather than religious.

The most dangerous food is that which, having been cooked, is then reheated. At certain temperatures germs spring to life with a vengeance, particularly in meat and quite horrifically in sausage. The simple way to avoid this danger is to make sure that food is served either thoroughly cooked and piping hot, or cold. Of course, this leaves your poor old salade de canard tiède (warm salad of medium rare duck breasts and vegetables) out in the cold, but some gourmets are happy to take a chance.

Sadly, fish is a well-known source of poisoning, and fish allergies are common. Although it’s not likely to be a danger to Westerners, there is some curio value in mentioning the highly dangerous puffer fish, so called because when threatened, it gulps water and doubles its mass, making it harder to swallow. The trade-off is a 50 percent reduction in speed of withdrawal. Other names for this fish, of which there are more than a hundred species worldwide, ranging in size from a few inches to two feet, are blow fish, swell fish, globe fish and, in Japan, where it’s considered a great delicacy, fugu. Many parts of this fish, including the liver, skin, and ovaries, contain a strong paralyzing poison, 1,000 times more deadly than cyanide, called tetrodotoxin. There is no known antidote for this poison. The immediate symptoms of ingestion are a slight numbness of the lips and tongue. Diarrhea, vomiting, collapse, and paralysis follow. Eventually, the central nervous system is destroyed, and the patient dies between 20 minutes and eight hours later, often remaining mentally lucid to the end. In Japan, only specially trained and licensed chefs are allowed to prepare fugu. There have been many casualties over the years. Some call this dish the gourmet’s Russian Roulette. Read that sushi menu carefully.

At the risk of sounding gruesome, it should be mentioned that ordinary (i.e., ghastly but non–life-threatening fish poisoning) will often produce the same immediate symptoms, as well as fierce facial flushing, which will sometimes reduce the sympathy factor as beholders assume the poor victim is simply drunk.

Fortunately, there is usually no mistaking fish that has deteriorated, but accidents do happen, and even the strong smell of rotting fish might get lost in the jumble of aromas that pervades the kitchen at busy times. Interestingly, fish inspectors at central markets are often allergic to the histamines that occur in deteriorating fish. Their noses are thus super-sensitive. One threatening whiff will define the quality of a batch of fish.

A properly trained Western cook simply follows the maxim, “When in doubt, throw it out.” But anyone unfamiliar with the fundamentals of hygiene should make an effort to acquire them.

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In its broadest sense, science (from the Latin scientia, meaning "knowledge") refers to any systematic knowledge or practice. In its more usual restricted sense, science refers to a system of acquiring knowledge based on scientific method, as well as to the organized body of knowledge gained through such research.

Fields of science are commonly classified along two major lines: natural sciences, which study natural phenomena (including biological life), and social sciences, which study human behavior and societies. These groupings are empirical sciences, which means the knowledge must be based on observable phenomena and capable of being experimented for its validity by other researchers working under the same conditions.